Phosphogypsum-Based Ultra-Low Basicity Cementing Material

Zhang, Xinxing; Zhong, Minlin; Zhang, Fan; Xiong, Jianbo; Zhang, Zhijie

doi:10.3390/ma15196601

Cited by 5 publications

(3 citation statements)

References 17 publications

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“…The X-ray photoelectron spectroscopy (XPS) analysis shows that fluorine impurities in phosphogypsum include sodium fluorosilicate, potassium fluorosilicate, fluorophosphoric acid, calcium fluoride, magnesium fluoride, and aluminum fluoride. Using a combination of X-ray photoelectron spectroscopy (XPS) and electron microprobe (EMPA), Zhao et al [90] Li et al [107] pointed out that the content of soluble fluorine in phosphogypsum increases with an increase in gypsum particle size. Peng et al [108] found that soluble fluorine in phosphogypsum is mainly distributed on the surface of gypsum crystals using SEM/EDXA analysis.…”

Section: Fluorine Impuritiesmentioning

confidence: 99%

Review of the State of Impurity Occurrences and Impurity Removal Technology in Phosphogypsum

Liu

2023

Materials

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A variety of co-existing impurities in phosphogypsum limit its large-scale and high-value utilization. This paper summarizes the common contents of major impurity components (silicon and phosphorus) and trace impurity components (fluorine, iron, aluminum, and carbon) in phosphogypsum and discusses the harm of impurity components to the comprehensive utilization of harmless phosphogypsum chemical resources. The occurrence status of impurity components in phosphogypsum and the research progress of various impurity removal technologies are summarized, and the effects of these impurity removal technologies on different contents of impurity components are evaluated. On this basis, the goal of improving the whiteness of phosphogypsum samples and the development of technology for further removal of impurities in phosphogypsum to improve the purity of the main content of calcium sulfate are speculated.

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Section: Fluorine Impuritiesmentioning

confidence: 99%

Review of the State of Impurity Occurrences and Impurity Removal Technology in Phosphogypsum

Liu

2023

Materials

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“…The binding material with ultra-low alkalinity based on industrial wastes of phosphogypsum, granulated blast-furnace slag, and sulfoaluminate cement, which was obtained in [26], has a broad application in the construction of islands, reefs, and river restoration. The new type of binder allows the use of a large amount of industrial waste and has the advantages of short setting time, low heat of hydration, high strength of the cement slurry, and the ability to fix harmful substances in phosphogypsum, such as phosphates, fluorides, and Cr and Ba elements.…”

Section: Introductionmentioning

confidence: 99%

Production Waste Management: Qualitative and Quantitative Characteristics and the Calculation of the Hazard Class of Phosphogypsum

Seraya,

Litvinov,

Daumova

et al. 2023

Processes

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Phosphogypsum (PG: CaSO4·2H2O) is a waste product (or by-product) from the production of phosphoric acid, the main component in the production of concentrated simple and complex fertilizers. The world production of phosphogypsum exceeds 200 million tons per year. PG discharged into water bodies (seas, rivers) or disposed of in land dumps may contain elements (including heavy metals and radionuclides) in forms and concentrations that are toxic to ecosystems and human health, which raises concerns about its impact on the environment. The concentrations of these elements vary depending on the region where the raw material is mined and the process used to produce phosphoric acid. Given the significant volumes of phosphogypsum formed, an urgent problem is not only the development of methods for its disposal, but also a special, specific control over its composition after the release of PG and during its use for removal, transportation, and storage in dumps and sludge storages. This article presents the results of comprehensive studies on the determination of the chemical and mineralogical composition of by-products from an experimental plant for the processing of phosphate raw materials of the designed chemical complex of the EuroChem-Karatau company (Republic of Kazakhstan). Based on the conducted studies, it was established that, in terms of the total toxicity index, the studied wastes belong to the fourth hazard class (low-hazardous) with the possibility of processing for the purpose of their further use.

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“…Ground-granulated blast furnace slag (GGBS) is another frequently used SCM due to its beneficial effect in terms of workability, long-term mechanical properties of mortar and concrete [ 10 ], improved pore structure [ 11 ], reduced shrinkage, and better durability [ 12 ]. The replacement of OPC by phosphogypsum, a by-product of fertilizer manufacturing, has also recently been recognized to have beneficial effects in terms of the elastic, mechanical, and durability properties of mortar and concrete [ 13 , 14 , 15 ]. However, in the case of phosphogypsum, a setting retarder is recommended.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Pore Structure in Cement Pastes with Micronized Natural Zeolite

et al. 2023

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The continuous development of urban areas around the world led to an increase in construction material use and demand, with concrete seeing significant market uptake. Although significant progress has been made to reduce the environmental impact of concrete, there is still a stringent need for improvement. One of the most widely used methods to reduce the environmental impact of the cement industry and the construction industry alike is the replacement of ordinary Portland cement (OPC) by supplementary cementitious materials (SCM). Aside from by-products of industry, SCMs could also come from natural sources. Taking into account the porous structure of zeolites and their contribution to the improvement of the mechanical and durability properties of cement-based materials, the analysis of pore structure in cement pastes incorporating micronized natural zeolite is deemed necessary. In this research, the OPC was replaced by zeolite in three different percentages: 10%, 20%, and 30% by mass. The evolution of pore structure was investigated by means of nuclear magnetic resonance relaxometry at the curing ages of 1, 7, and 28 days. The microstructure of cement pastes was assessed by scanning electron microscopy investigations at 1, 7, 14, 21, and 28 days. The obtained results show that smaller pore sizes are present in cement pastes containing zeolites during the first 7 days. However, at the age of 28 days, the reference mix exhibits a similar pore structure to the mix containing 10% micronized zeolite due to the presence of larger amounts of hydration products. Increasing the replacement percentage to 30% results in larger pores, as indicated by larger values of the relaxation time.

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Phosphogypsum-Based Ultra-Low Basicity Cementing Material

Cited by 5 publications

References 17 publications

Review of the State of Impurity Occurrences and Impurity Removal Technology in Phosphogypsum

Review of the State of Impurity Occurrences and Impurity Removal Technology in Phosphogypsum

Production Waste Management: Qualitative and Quantitative Characteristics and the Calculation of the Hazard Class of Phosphogypsum

Analysis of Pore Structure in Cement Pastes with Micronized Natural Zeolite

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